Core was generated by `/usr/sbin/asterisk -f -U asterisk -G asterisk -vvvg -c'.
Program terminated with signal 11, Segmentation fault.
#0  0x007fd39c in pthread_mutex_lock () from /lib/libpthread.so.0
(gdb) bt
#0  0x007fd39c in pthread_mutex_lock () from /lib/libpthread.so.0
#1  0x080d63e7 in ast_rtp_read (rtp=0x8f09250) at /home/src/asterisk/asterisk-1.4.21.2/include/asterisk/lock.h:755
#2  0x00afe4a3 in sip_read (ast=0x8f02750) at chan_sip.c:4367
#3  0x080858a3 in __ast_read (chan=0x8f02750, dropaudio=0) at channel.c:2071
#4  0x0808650c in ast_waitfordigit_full (c=0x8f02750, ms=75, audiofd=-1, cmdfd=-1) at channel.c:2348
#5  0x08086868 in ast_waitfordigit (c=0x8f02750, ms=100) at channel.c:1791
#6  0x001fc476 in common_exec (chan=0x8f02750, flags=0xb788ee88, volfactor=0, fd=0, mygroup=0xb788de44 "3633", spec=0x0, 
    exten=0x0, context=0x0) at app_chanspy.c:527
#7  0x001fd405 in chanspy_exec (chan=0x8f02750, data=0xb7890f08) at app_chanspy.c:740
#8  0x080caa8b in pbx_extension_helper (c=0x8f02750, con=0x0, context=0x8f028d0 "dialout", exten=0x8f02920 "83633", priority=1, 
    label=0x0, callerid=0x8e96718 "3399", action=E_SPAWN) at pbx.c:537
#9  0x080cd0d2 in __ast_pbx_run (c=0x8f02750) at pbx.c:2317
#10 0x080ce08e in pbx_thread (data=0x8f02750) at pbx.c:2636
#11 0x080fc03b in dummy_start (data=0x8e94fc8) at utils.c:895
#12 0x007fb46b in start_thread () from /lib/libpthread.so.0
#13 0x00473dbe in clone () from /lib/libc.so.6